Heater trips the circuit breaker or RCD as soon as it is switched on.

Safety: Do not repeatedly reset a tripping breaker or RCD. There is a real risk of fire or electric shock.

Steps:

• Inspect for water leaks: With power off, remove the lower cover and check for water around the element flange and wiring. Fix any leaks before proceeding.
• Check terminal block: Look for burned or shorted connections at the mains terminal block. Replace damaged parts.
• Test element: Disconnect the element wires and try powering the heater (controls only). If the breaker no longer trips, the element is likely shorted and must be replaced.
• Insulation test: Use a megohmmeter to test insulation between element terminals and ground. Low resistance indicates leakage.

If the breaker still trips with the element disconnected, the fault may be in the control PCB or wiring; professional service is recommended.